Change format of -X arguments to require value after '='

Report a warning when an argument is passed in the old form (with the
whitespace)

 #KT-17264 Fixed

compiler/testData/cli/js/jsExtraHelp.out

@@ -2,10 +2,10 @@ Usage: kotlinc-js <options> <source files>
 where advanced options include:
   -Xtypedarrays              Translate primitive arrays to JS typed arrays
   -Xno-inline                Disable method inlining
-  -Xrepeat <count>           Repeat compilation (for performance analysis)
+  -Xrepeat=<count>           Repeat compilation (for performance analysis)
   -Xskip-metadata-version-check Load classes with bad metadata version anyway (incl. pre-release classes)
   -Xallow-kotlin-package     Allow compiling code in package 'kotlin'
-  -Xplugin <path>            Load plugins from the given classpath
+  -Xplugin=<path>            Load plugins from the given classpath
   -Xmulti-platform           Enable experimental language support for multi-platform projects
   -Xno-check-impl            Do not check presence of 'impl' modifier in multi-platform projects
   -Xcoroutines={enable|warn|error} Enable coroutines or report warnings or errors on declarations and use sites of 'suspend' modifier

compiler/testData/cli/jvm/extraArgumentPassedInObsoleteForm.args

@@ -0,0 +1,5 @@
+-Xplugin
+non-existing-file.jar
+$TESTDATA_DIR$/simple.kt
+-d
+$TEMP_DIR$

compiler/testData/cli/jvm/extraArgumentPassedInObsoleteForm.out

@@ -0,0 +1,2 @@
+warning: advanced option value is passed in an obsolete form. Please use the '=' character to specify the value: -Xplugin=...
+OK

compiler/testData/cli/jvm/extraHelp.out

@@ -6,18 +6,18 @@ where advanced options include:
   -Xreport-perf              Report detailed performance statistics
   -Xmultifile-parts-inherit  Compile multifile classes as a hierarchy of parts and facade
   -Xskip-runtime-version-check Allow Kotlin runtime libraries of incompatible versions in the classpath
-  -Xdump-declarations-to <path> Path to JSON file to dump Java to Kotlin declaration mappings
+  -Xdump-declarations-to=<path> Path to JSON file to dump Java to Kotlin declaration mappings
   -Xsingle-module            Combine modules for source files and binary dependencies into a single module
   -Xadd-compiler-builtins    Add definitions of built-in declarations to the compilation classpath (useful with -no-stdlib)
   -Xload-builtins-from-dependencies
                              Load definitions of built-in declarations from module dependencies, instead of from the compiler
-  -Xscript-resolver-environment <key=value[,]>
+  -Xscript-resolver-environment=<key=value[,]>
                              Script resolver environment in key-value pairs (the value could be quoted and escaped)
   -Xno-inline                Disable method inlining
-  -Xrepeat <count>           Repeat compilation (for performance analysis)
+  -Xrepeat=<count>           Repeat compilation (for performance analysis)
   -Xskip-metadata-version-check Load classes with bad metadata version anyway (incl. pre-release classes)
   -Xallow-kotlin-package     Allow compiling code in package 'kotlin'
-  -Xplugin <path>            Load plugins from the given classpath
+  -Xplugin=<path>            Load plugins from the given classpath
   -Xmulti-platform           Enable experimental language support for multi-platform projects
   -Xno-check-impl            Do not check presence of 'impl' modifier in multi-platform projects
   -Xcoroutines={enable|warn|error} Enable coroutines or report warnings or errors on declarations and use sites of 'suspend' modifier

compiler/testData/cli/jvm/pluginSimple.args

@@ -1,10 +1,9 @@
 -d
 $TEMP_DIR$
--Xplugin
-dist/kotlinc/lib/android-extensions-compiler.jar
+-Xplugin=dist/kotlinc/lib/android-extensions-compiler.jar
 -P
 plugin\:org.jetbrains.kotlin.android\:package=com.myapp
 -P
 plugin\:org.jetbrains.kotlin.android\:variant=main;$TESTDATA_DIR$/androidPlugin/res
 $TESTDATA_DIR$/pluginSimple.kt
-$TESTDATA_DIR$/androidPlugin
+$TESTDATA_DIR$/androidPlugin

compiler/testData/cli/jvm/pluginSimpleUsage.args

@@ -1,7 +1,6 @@
 -d
 $TEMP_DIR$
--Xplugin
-dist/kotlinc/lib/android-extensions-compiler.jar
+-Xplugin=dist/kotlinc/lib/android-extensions-compiler.jar
 -P
 plugin\:org.jetbrains.kotlin.android\:package=com.myapp
 $TESTDATA_DIR$/pluginSimple.kt
@@ -11,4 +10,4 @@ $TESTDATA_DIR$/androidPlugin/androidWidget.kt
 $TESTDATA_DIR$/androidPlugin/fakeAppwidgetPackage.kt
 $TESTDATA_DIR$/androidPlugin/fakeInputMethodServicePackage.kt
 $TESTDATA_DIR$/androidPlugin/fakeOpenglPackage.kt
-$TESTDATA_DIR$/androidPlugin/fakeWebkitPackage.kt
+$TESTDATA_DIR$/androidPlugin/fakeWebkitPackage.kt