doc: clarify build support text

Revise compilation/execution support text to keep it shorter, simpler,
and hopefully easier to read/understand.

PR-URL: #30899
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Jiawen Geng <[email protected]>

Author: Trott

BUILDING.md

@@ -84,12 +84,10 @@ will be updated to reflect those changes.
 
 ### Platform list
 
-Compiling and running Node.js is supported for a limited set of operating
-systems, architectures and libc versions. The table below lists the
-combinations that the core team has committed to supporting and the nature of
-that support as per the support tiers above. A list of
-[supported compile toolchains](#supported-toolchains) is also supplied for
-tier 1 platforms.
+Node.js compilation/execution support depends on operating system, architecture,
+and libc version. The table below lists the support tier for each supported
+combination. A list of [supported compile toolchains](#supported-toolchains) is
+also supplied for tier 1 platforms.
 
 **For production applications, run Node.js on supported platforms only.**