add dir='ltr' to non-localized debug toolbar stuff

add dir='ltr' to non-localized debug toolbar stuff

It might be nice to localize this stuff; until then,
it is rather annoying to look at broken parentheses
when using MediaWiki and the toolbar in a RTL language.

Removed text-align: left, so it won't be flipped.

Added an explicit label for Peak memory - it's clearer and it helps
with LTR layout (the units are localized and confuse the display).

Added lang="en" dir="ltr" to the main containter, which is
the right thing until it's properly localized.

Change-Id: I1d0ef6d12eefac0ff28277e4cc2dbc62acd9eee2