RFR: 8306408: Fix the format of several tables in building.md [v4]

[Dingli Zhang]

> Hi all,
> 
> Currently, the format of several tables in building.md looks a little 
> problematic and will incorrectly display the split line. In contrast, the 
> corresponding building.html will display the tables correctly.
> 
> This patch will only change building.md and the format of the tables 
> will display correctly.
> 
> Please take a look and have some reviews. Thanks a lot.

Dingli Zhang has updated the pull request incrementally with one additional commit since the last revision:

  Updated html

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/13523/files
  - new: https://git.openjdk.org/jdk/pull/13523/files/aaf29afd..9c237f95

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13523&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13523&range=02-03

  Stats: 8 lines in 1 file changed: 0 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/13523.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13523/head:pull/13523

PR: https://git.openjdk.org/jdk/pull/13523