[minor] test infrastructure: fix default handling in proc launcher

plugins/scripting/scripting-compiler/tests/org/jetbrains/kotlin/scripting/compiler/plugin/ScriptingWithCliCompilerTest.kt

@@ -73,7 +73,6 @@ class ScriptingWithCliCompilerTest {
                 "-expression",
                 "\\@file:CompilerOptions(\"-Xunknown1\")"
             ),
-            listOf(""),
             expectedExitCode = 1,
             expectedSomeErrPatterns = listOf(
                 "unresolved reference: CompilerOptions"
@@ -89,7 +88,6 @@ class ScriptingWithCliCompilerTest {
                 "-expression",
                 "\\@file:CompilerOptions(\"-Xunknown1\")"
             ),
-            listOf(""),
             expectedExitCode = 1,
             expectedSomeErrPatterns = listOf(
                 "expecting an element"
@@ -109,7 +107,6 @@ class ScriptingWithCliCompilerTest {
                 "-script",
                 scriptFile.path
             ),
-            listOf(""),
             expectedExitCode = 1,
             expectedSomeErrPatterns = listOf(
                 "unrecognized script type: someScript.+"
@@ -122,7 +119,6 @@ class ScriptingWithCliCompilerTest {
                 "-script",
                 scriptFile.path
             ),
-            listOf(""),
             expectedExitCode = 1,
             expectedSomeErrPatterns = listOf(
                 "error: invalid argument: -abracadabra"
@@ -135,7 +131,6 @@ class ScriptingWithCliCompilerTest {
                 "-script",
                 scriptFile.path
             ),
-            listOf(""),
             expectedExitCode = 1,
             expectedSomeErrPatterns = listOf(
                 "error: invalid argument: -abracadabra"

plugins/scripting/scripting-compiler/tests/org/jetbrains/kotlin/scripting/compiler/plugin/testUtil.kt

@@ -177,7 +177,7 @@ fun runWithK2JVMCompiler(
         )
     }
     try {
-        val outLines = out.lines()
+        val outLines = if (out.isEmpty()) emptyList() else out.lines()
         Assert.assertEquals(
             "Expecting pattern:\n  ${expectedAllOutPatterns.joinToString("\n  ")}\nGot:\n  ${outLines.joinToString("\n  ")}",
             expectedAllOutPatterns.size, outLines.size