Get rid of kotlinx-coroutines usage in scripting libs and plugins

the dependency on the coroutines library caused various problems like
KT-30778, or stdlib/runtime version conflicts.
The only function used was `runBlocking`, so this change replaces it
with the internal implementation based on the similar internal thing
from the stdlib.
#KT-30778 fixed

libraries/examples/scripting/jvm-maven-deps/script/build.gradle.kts

@@ -7,6 +7,7 @@ dependencies {
     compile(project(":kotlin-scripting-jvm"))
     compile(project(":kotlin-scripting-dependencies"))
     compile(project(":kotlin-scripting-dependencies-maven"))
+    compile(commonDep("org.jetbrains.kotlinx", "kotlinx-coroutines-core"))
 }
 
 sourceSets {