RFR 8214310: SymbolTable: Use get and insert

[Gerard Ziemski]

Hi all,

Please review this fix, which is similar to 8213791, but here we implement it for the SymbolTable, whereas before we did it for the StringTable.

I’d like to see this go in JDK12, but if we determine that there is any part of it that is too controversial, I’m OK with waiting for JDK13

References:

bug id: https://bugs.openjdk.java.net/browse/JDK-8214310
webrev: http://cr.openjdk.java.net/~gziemski/8214310_rev1
tests:  passes Mach5 hs_tier1,2,3,4,5


Cheers