Investigate recent 32bit compiler performance regressions

In c5088e29 I tweaked the numbers for the x86/Linux build to get them to pass for the RC, but some of these look pretty bad.

Most of them shot up quite a bit. Some of them I don't think were very recent (modification date unspecified, etc.) A few others had updates as early as November, so something has clearly slipped on 32bit platforms here.

I spent a tiny amount of time investigating, but didn't get very far. I'm not holding the RC for these, but it's worth investigating when we get a chance.

Trac metadata

Trac field	Value
Version	7.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed milestone to %7.8.1

changed weight to 5

added Tbug Trac import labels

changed weight to 7

Trac metadata

Trac field	Value
Priority	normal → high

I'm double checking this because I may have accidentally made an error in my build settings. Will report back.

closed

This turned out to be bogus, my bad! Most of the numbers look OK.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedInvalid

added compiler perf label

added Phigh label