a few bugs in symtable related to scope management on errors

[iritkatriel]

On code inspection, there are a few places where scope is not existed in an error path.

Linked PRs

• gh-156525: fix a few error path scope management bugs in symtable #156526
• [3.15] gh-156525: fix a few error path scope management bugs in symtable (GH-156526) #156532
• [3.14] gh-156525: fix a few error path scope management bugs in symtable (GH-156526) #156533