8349075: Once again allow -compilejdk in JAVA_OPTIONS

Reviewed-by: rehn, erikj

make/RunTests.gmk

@@ -75,9 +75,6 @@ endif
 
 # This is the JDK that we will test
 JDK_UNDER_TEST := $(JDK_IMAGE_DIR)
-# The JDK used to compile jtreg test code. By default it is the same as
-# JDK_UNDER_TEST.
-JDK_FOR_COMPILE := $(JDK_IMAGE_DIR)
 
 TEST_RESULTS_DIR := $(OUTPUTDIR)/test-results
 TEST_SUPPORT_DIR := $(OUTPUTDIR)/test-support
@@ -945,6 +942,11 @@ define SetupRunJtregTestBody
     $1_JTREG_BASIC_OPTIONS += -e:JIB_HOME=$$(JIB_HOME)
   endif
 
+  ifneq ($$(JDK_FOR_COMPILE), )
+    # Allow overriding the JDK used for compilation from the command line
+    $1_JTREG_BASIC_OPTIONS += -compilejdk:$$(JDK_FOR_COMPILE)
+  endif
+
   $1_JTREG_BASIC_OPTIONS += -e:TEST_IMAGE_DIR=$(TEST_IMAGE_DIR)
 
   $1_JTREG_BASIC_OPTIONS += -e:DOCS_JDK_IMAGE_DIR=$$(DOCS_JDK_IMAGE_DIR)
@@ -997,7 +999,6 @@ define SetupRunJtregTestBody
       $$(JTREG_JAVA) $$($1_JTREG_LAUNCHER_OPTIONS) \
           -Dprogram=jtreg -jar $$(JT_HOME)/lib/jtreg.jar \
           $$($1_JTREG_BASIC_OPTIONS) \
-          -compilejdk:$$(JDK_FOR_COMPILE) \
           -testjdk:$$(JDK_UNDER_TEST) \
           -dir:$$(JTREG_TOPDIR) \
           -reportDir:$$($1_TEST_RESULTS_DIR) \