Modify lldbbench.py so that lldbtest.line_number() utility function is available to
BenchBase client as just line_number(), and modify lldbtest.py so that self.lldbExec
(the full path for the 'lldb' executable) is available to BenchBase client as well.

An example run of the test case on my MacBook Pro running Lion:

1: test_compare_lldb_to_gdb (TestRepeatedExprs.RepeatedExprsCase)
   Test repeated expressions with lldb vs. gdb. ... 
lldb_avg: 0.204339
gdb_avg: 0.205721
lldb_avg/gdb_avg: 0.993284
ok

llvm-svn: 136740

llvm-svn: 136666

Stopwatch (self.swatch) within the BenchBase's setUp() instance method to be available
to all the child classes.

Use self.swatch to measure elapsed time in TestRepeatedExprs.py, which needs to be
modified later on to actually measure repeated expression evaluations within the
context of lldb as well as gdb.

llvm-svn: 136664

Modify the example TestRepeatedExprs.py to use BenchBase, instead.

llvm-svn: 136649