RFR: JDK-8230715: Baseline compare build on Windows fails intermittently in file type for jvm.pdb

[Erik Joelsson]

The baseline compare builds on Windows fails intermittently. The output 
of the file command for jvm.pdb is not entirely stable. I have now seen 
a handful of failures over the last month looking like this:

[2019-08-20T20:34:25,887Z] JDK File types...
[2019-08-20T20:34:25,902Z] other: ./bin/server/jvm.pdb: MSVC program 
database ver 7.00, 4096*18031 bytes
[2019-08-20T20:34:25,902Z] this : ./bin/server/jvm.pdb: MSVC program 
database ver 7.00, 4096*18033 bytes
[2019-08-20T20:35:20,152Z] Test File types...
[2019-08-20T20:35:20,152Z] other: ./bin/server/jvm.pdb: MSVC program 
database ver 7.00, 4096*18031 bytes
[2019-08-20T20:35:20,152Z] this : ./bin/server/jvm.pdb: MSVC program 
database ver 7.00, 4096*18033 bytes

We don't want to rely on the file command to compare file sizes, so I've 
implemented a special case for this type of file.

Bug: https://bugs.openjdk.java.net/browse/JDK-8230715

Webrev: http://cr.openjdk.java.net/~erikj/8230715/webrev.01/

/Erik