patch 8.2.2757: Vim9: blob tests for legacy and Vim9 script are separate

Problem:    Vim9: blob tests for legacy and Vim9 script are separate.
Solution:   Add CheckLegacyAndVim9Success().  Make blob index assign work.
diff --git a/src/vim9.h b/src/vim9.h
index c30e597..4a10e12 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -57,6 +57,8 @@
     ISN_STORENR,    // store number into local variable isn_arg.storenr.stnr_idx
     ISN_STOREINDEX,	// store into list or dictionary, type isn_arg.vartype,
 			// value/index/variable on stack
+    ISN_STORERANGE,	// store into blob,
+			// value/index 1/index 2/variable on stack
 
     ISN_UNLET,		// unlet variable isn_arg.unlet.ul_name
     ISN_UNLETENV,	// unlet environment variable isn_arg.unlet.ul_name